Asymmetrical Bearing Pockets in Rotary Compressors
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Solution Overview
Problem
In rotary compressors, the asymmetrical shape of the hybrid cylinder's inner peripheral surface affects the efficiency by creating a separation space between the vane and the cylinder, leading to increased friction loss and decreased compression efficiency, particularly when the suction and discharge ports are adjacent, which complicates the compression process.
Innovation Solution
The design includes a rotational shaft supported by first and second bearings, with a cylinder forming a compression space and a rotor that compresses refrigerant, featuring asymmetrical pockets on the bearing surfaces to prevent refrigerant leakage and improve efficiency. The vane's contact with the cylinder's inner surface is optimized by adjusting the overlapping lengths and pressures within the pockets, ensuring efficient compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the suction port and discharge port are sequentially formed adjacent to each other in a direction opposite to the rotational direction of the roller to achieve a high compression ratio, then the compression ratio is improved, but a separation space is generated between the vane and the cylinder, causing compression efficiency to decrease
Solution Approach 1:
The patent applies local quality by creating an asymmetrical pocket structure in the bearing with different depths in different regions. The pocket has a first region with a first depth and a second region with a second depth greater than the first depth, allowing different local pressures to be applied to the vane at different locations, thereby maintaining vane-cylinder contact while achieving high compression ratio
Solution Approach 2:
The patent uses the asymmetrical pocket to create equipotential pressure distribution that prevents separation. By carefully designing the pocket geometry with different depths, the pressure is distributed to maintain the vane in contact with the cylinder inner peripheral surface throughout the compression cycle, eliminating the separation space that would otherwise reduce efficiency
2Device complexity
If the inner peripheral surface of the cylinder is formed in a circular shape, then the structure is simple, but friction loss increases compared to an asymmetrical hybrid cylinder
Solution Approach 1:
The patent applies asymmetry by forming the inner peripheral surface of the cylinder in an elliptical shape rather than a circular shape. This asymmetrical geometry allows the vane to maintain better contact with the cylinder surface during rotation, reducing separation space and friction loss while improving compression efficiency
Solution Approach 2:
The asymmetrical pocket in the bearing creates local quality differences in pressure distribution, with different depths in different regions allowing optimized contact pressure at the vane-cylinder interface, reducing friction loss in critical areas
3Duration of action of moving object
If the vane is slidably inserted into the rotor to rotate with the roller, then the compression process is continuous, but friction loss increases due to contact between the vane and cylinder
Solution Approach 1:
The asymmetrical pocket creates a pressure field that maintains equipotential contact between the vane and cylinder, ensuring continuous compression while minimizing separation and reducing friction loss through optimized pressure distribution
Data Source
AI summary
A rotary compressor is provided that may include a rotational shaft, first and second bearings configured to support the rotational shaft in a radial direction, a cylinder disposed between the first and second bearings to form a compression space, a rotor disposed in the compression space and coupled to the rotational shaft to compress a refrigerant as the rotor rotates, and at least one vane slidably inserted into the rotor, the at least one vane coming into contact with an inner peripheral surface of the cylinder to separate the compression space into a plurality of regions. At least one of the first bearing and the second bearing may include first and second pockets formed on a surface facing the rotor, and at least one of the first pocket and the second pocket may be formed in an asymmetrical shape.